Materials Literature
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We discuss the local cutting of single-walled carbon nanotubes by a voltage pulse to the tip of a scanning tunneling microscope. The tip voltage ($\mid V \mid \ge $~3.8 eV) is the key physical quantity in the cutting process. After reviewing several possible physical mechanisms we conclude that the cutting process rel…
We study effective-medium approximations for linear composite media by means of a path integral formalism with replicas. We show how to recover the Bruggeman and Hori-Yonezawa effective-medium formulas. Using a replica-coupling ansatz, these formulas are extended into new ones which have the same percolation threshold…
An effective-medium theory is proposed for random weakly nonlinear dielectric media. It is based on a new gaussian approximation for the probability distributions of the electric field in each component of a multi-phase composite. These distributions are computed to linear order from a Bruggeman-like self-consistent f…
Self-consistent field theory predicts that the complex phase behavior of block copolymers does not originate solely from the interface seeking constant mean curvature as once thought, but instead reflects competing minimization of interfacial tension and packing frustration. To test this prediction, we directly measur…
Luminescence of Nd(III) in an organic solvent having C-H bonds was achieved for the first time by complexing Nd(III) with long-chain perfluoroalkylated ligands such as bis(perfluorooctylsulfonyl)aminate (pos). The complex [Nd(pos)(3)] gave an emission quantum yield of 3.0+/-0.5 % in undeuterated acetone. The bulky pos…
We present a comprehensive study of the partially reduced polyoxomolybdate [H3-Mo57V6(NO)6O183(H2O)18]21-encapsulated in a shell of dimethyldioctadecylammonium (DODA) surfacmolecules. Treatment of an aqueous solution of (NH4)21[H3Mo57V6-(NO)6O183(H2O)18] . 65H2O (1a) with a trichloromethane solution of the surfactant…
Recent studies have shown a current limiting effect in the field emission behavior of carbon nanotubes. In this letter, we demonstrate that an individual nanotube exhibits current saturation above 100 nA of emission current, and we show that this current saturation is a direct result of an adsorbate-enhanced field emi…
Aluminum-doped zinc oxide (AZO) thin films (∼3000 Å) with low electrical resistivity and high optical transparency have been grown by pulsed-laser deposition on glass substrates without a postdeposition anneal. Films were deposited at substrate temperatures ranging from room temperature to 400 °C in O2 partial pressur…
An approximate expression for the free energy of a single crystal is derived to determine equilibrium positions of atoms on vicinal faces of a fcc crystal at various temperatures thermodynamically. The obtained free energy has a peculiarity (critical temperature) in all the considered cases: infinite crystal, low-inde…
This article describes the effect of the target magnetic field on the plasma process and the physical properties of films deposited by magnetically controlled rf and dc planar magnetron sputtering techniques. The target magnetic field, which is parallel to the target surface, is controlled and its’ strength is a key p…
Many experimental studies of protein deposition on solid surfaces involve alternating adsorption/desorption steps. In this paper, we investigate the effect of a desorption step (separating two adsorption steps) on the kinetics, the adsorbed-layer structure, and the saturation density. Our theoretical approach involves…
The opdA (prlC) gene of Salmonella enterica serovar Typhimurium and Escherichia coli encodes the metalloprotease oligopeptidase A (OpdA). We report that opdA is cotranscribed with a downstream open reading frame, yhiQ. Transcription of this operon is induced after a temperature shift (30 to 42 degrees C), and this ind…
BiSeI crystals obtained by a chemical-transport reaction are orthorhombic (space group Pnma) with a = 8.6967 (17) Å, b = 4.2205 (8) Å and c = 10.574 (2) Å. It could be confimed that BiSeI crystallizes in the centrosymmetric SbSI structure type.
Oxygen ion and neutral atom yields were measured for ${\mathrm{O}}^{+}$ and ${\mathrm{O}}^{\ensuremath{-}}$ ions incident on a clean Cu(001) surface for ion energies from 0.4 to 5 keV. Scattering geometries were chosen that simplify the selection of single collisions between the incident ions and surface atoms and con…
The local environment of Cm3+ in a borosilicate glass has been probed by a combination of laser spectroscopy, structural modeling, and extended x-ray absorption fine structure (EXAFS) spectroscopy. The Stark splitting for the Cm f–f state transitions is significantly larger than the inhomogeneous line broadening that…
Magnetic and magnetostrictive properties have been investigated for amorphous (Tb0.27Dy0.73)(Fe1−xCox)2 thin films. An increase in the 3d magnetic moment due to the enhancement of T–T interactions in substituted (Fe, Co) alloys was found. This leads to stronger R–(Fe, Co) exchange energies and then to enhancements of…
The electronic properties and the crystal structure of layered perovskite-related niobates ${\mathrm{Sr}}_{1\ensuremath{-}y}{\mathrm{La}}_{y}{\mathrm{NbO}}_{3.5\ensuremath{-}x}$ can be tuned by gradually changing the oxygen stoichiometry. We have studied the electronic structure of this series in detail by angle-integ…
A novel segmented block copolymer, containing polyethylene glycol segment and GlyAlaGlyAla sequence derived from B. mori silk, has been prepared as a model for silk-based materials using both solution and interfacial techniques. Inherent viscosity, size exclusion chromatography, and light-scattering measurements gave…
The changes in the photoconductivity of hydrogenated tetrahedral amorphous carbon (ta-C:H) with nitrogen incorporation were studied. Low level nitrogen incorporation improves the photoconductivity, by shifting the Fermi level upwards in the band gap. Films with a photosensitivity of about 200 at room temperature under…
Novel thermoplastic elastomers (TPEs) consisting of poly(isobutylene-b-indene) (PIB-b-PInd) arms radiating from hexamethylcyclohexasiloxane (D) cores were prepared, characterized, and their properties investigated. The syntheses of these star-blocks involved the linking by hydrosilation of PInd-b-PIBCH2CHCH2 prearm…